What is happening on my bush's branches?

[joezapp]

I have this bush many years. It may be a rhodendum. Very nice bush with pretty lavender colored flowers in May. As you can see, it has finished flowering. Much to my surprise, these white balls have now appeared on many of the branches. They are white balls with an opening and grey matter sticking out. They have looked the same for the past 3 weeks. No changes. Has anyone seen this before? Any ideas?

[applestar]

I thought those are scale specific to rhodos and azaleas, so I looked them up.
See if these fit --

Thin azaleas with crusty stems may have azalea bark scale | MSU Extension

https://msue.anr.msu.edu/news/thin_azale ... bark_scale

look for a crusty covering of scale insects on the stems, or white, waxy egg masses produced by the females (see photos). Infested stems and leaves under infested stems may also turn black from the black, sooty mold fungus that grows on the sugary liquid waste excreted by the scale insects.

As mentioned here, I would start by just picking off scattered infestation -- rubbing alcohol+light oil like canola mix on cotton swabs or bamboo chopstick scored and wrapped with cotton (I use the vitamin jar cotton) -- and cutting off heavily infested branches. Though you may still end up needing to spray, I prefer to leave as last resort because these sprays will also kill their natural predators.

HGIC 2051 Azalea & Rhododendron Insect Pests : Extension : Clemson University : South Carolina

https://www.clemson.edu/extension/hgic/p ... c2051.html

Control: A light infestation of scale can be scraped off the plant and discarded, or heavily infested branches may be pruned out. A horticultural oil spray applied in early spring before new foliar growth begins will kill many over-wintering adults and eggs by smothering them. Spraying horticultural oil during the growing season will help control crawlers, as well as adults and eggs. Apply horticultural oil sprays at a 2% solution (5 tablespoons oil per gallon of water). Spray the plants thoroughly, so that the oil spray drips or "runs off" from the upper and under sides of leaves, twigs, and plant stems.

[joezapp]

Thank you for researching this for me. After looking at a lot of images online, I have come across some that seem to look similar to my situation. There are a lot of varieties of scale. I will assume that these are scale attached to my branches sucking sap under a protective coating.

I do spray 3 times every spring because we have a borer problem in this area that I keep under control by spraying. After the upcoming final spray, I will remove all the white sacs that I see.

Thanks again!

[applestar]

Is it a different species? Do you still have the link?

[joezapp]

Yes. This appears very similar. Cottony maple scale.

https://www.forestryimages.org/browse/de ... um=5360709

[joezapp]

So my next and final pesticide spraying of the season (to control borers) is nearly 2 weeks away. The infested branches were exposed to the last insecticide treatment 2 1/2 weeks ago, which I'm sure helped somewhat, even with the cottony protection. But then I thought to myself, "Why am I leaving the 'cottony maple scale' on the branches to feed and do damage for another 2 weeks"? Seemed silly to me. So this morning I hosed all the white cotton off. Seemed like a no-brainer. Indeed, it was apparent afterward that they were feeding on the branches.

Any living organisms will succumb to the treatment at month end. However, since they are no longer feeding, wouldn't they die anyway?

[applestar]

Thanks for posting the ID

Yeah if they hosed off I think your spray might have been effective in weakening if not killing them. I think removing was the right idea -- now the plant will have the chance to try to heal during the next two weeks

[joezapp]

Thanks for steering me in the right direction. Much appreciated. I did not expect this to be scale!